1. Field of he Invention
The present invention relates to computer graphics, and, more particularly, to a system and method to substantially increase the capability of a computer to present information.
2. Background of the Invention
Computers have vastly increased their ability to process information. Many computers now include one or more powerful microprocessors. Multi-tasking operating systems have given the computer the ability to execute more than one application at a time. Application programs have taken advantage of this increased computing power, and as a result, have become more graphic intensive.
The size of standard computer terminals (e.g., a 19 inch monitor) has become a limiting factor in presenting processed information to the user. A standard desktop computer now has the capability to inundate the display terminal of the computer with information. The computer industry has attempted several approaches to overcome this problem.
The most common approach has been window based software. Windowing systems attempt to maximize the use of the screen space of a display terminal by providing overlapping windows and icons. The window operating environment, although useful, is often frustrating to operate. The user is required to spend an inordinate amount of time moving, resizing, and opening and closing various windows and icons on the display space. The opening and closing of a window is often slow. Over-lapping windows can be aggravating to the eye. It is also difficult to manipulate information within windows. The physical size of the display terminal limits the size of each window, the number of windows that can be displayed at a given time, and in the case of graphic intensive applications, is often too small to display an image of an object in its entirety.
Another approach to increase the display surface area of a computer is to simply use a larger monitor. Several companies are marketing twenty-eight (28) inch diagonal monitors. These extra-large monitors do increase the display capabilities of the computer to some degree, but the problems outlined above are still present. These monitors are also prohibitively expensive to build and difficult to ship to customers. One such monitor currently on the market weighs over two hundred pounds and is more than thirty inches deep. This monitor is clearly impractical for standard desktop computers.
Virtual reality systems represent yet another approach to increasing the display area of a computer. It is believed a virtual reality system was first described by Ivan Sutherland, a co-inventor of the present application, in a seminal article entitled xe2x80x9cA head-mounted three dimensional displayxe2x80x9d, AFIPS Conference Proceedings, Volume 33, 1968. This article describes an imaging pipeline, including: a database for storing all the data, relationships and objects that are relevant to a model to be displayed; a position sensor for selecting a view point of the model to be displayed; a transformer for traversing the database, extracting the appropriate data to generate the model from the selected view point, and transforming it on the fly to a display format; a frame buffer for storing the transformed data; and the head mounted display for displaying the data stored in the frame buffer. The virtual reality system thus provides the user with a head-motion parallax: when the user moves his head, the view seen through the head mounted display unit changes as it would in real life.
It is believed that all current virtual reality systems, which use the basic pipeline described above, are limited in their performance. Only the current image, as seen in the head mounted display at a given time, is stored in the frame buffer of the system. When the user moves his head, a new scene must be calculated on the fly by the computer and stored in the frame buffer of the system. This causes a perceptible lag time between the selection of a new view point and the time the new image appears on the head mounted display. This lag is unnatural and uncomfortable to the user. Prolonged use of these virtual reality systems has been known to cause nausea.
The present invention is a system and method for a computer video display. The present invention provides an inexpensive, easy-to-use large display environment.
The computer video display system includes a frame buffer for storing a multiplicity of view points of a model to be displayed, a measurement device for ascertaining a point of view of the model to be displayed in response to the measurement of an aspect of the user""s movement, a computational device for modifying the view point according to a predefined algorithm, an access device for accessing the appropriate display information from the frame buffer, and a head mounted display for displaying the selected view point of the model. During operation, the measuring device, the view point device, and the computational device continuously update the view points of the model in response to movements of the user. In response thereto, the access device traverses the frame buffer and provides the updated display information to the head mounted display.
The display information is presented to the user in a view window in the head mounted display. To generate the view window, the computational device and the access device generate a plurality of scan lines from the frame buffer. The scan lines contain pixel information corresponding to the current point of view of the model to be displayed in the view window. For each view window in the preferred embodiment, nine hundred (900) scan lines are generated in the vertical direction, and each scan line is eleven hundred and twenty (1120) bits long in the horizontal direction.
In a preferred embodiment, the computer video display system provides a virtual view space which is in the shape of a 360xc2x0 cylinder and a height of 135xc2x0 surrounding the computer user. The virtual view space is mapped into the frame buffer in the computer system. As the user scans the virtual view space, the frame buffer is immediately traversed, and the view window as seen through the head mounted display is updated. As a result, the image, as seen through the head mounted display, appears to be continuous, fluid and natural.
The computer video display of the present invention provides a number of unique features and advantages. The user is immersed in a virtual view system, which provides the user with an almost inexhaustible image space. The user navigates the virtual view space in a natural manner by simply adjusting the measurement device. The frame buffer contains all the view points of the model to be displayed. The data, relationships and objects that are relevant to the points of view are stored in the frame buffer in the transformed state. This eliminates the need to calculate display information on the fly, store it in a frame buffer, and then display it, as is required in prior art virtual reality systems. Display information is retrieved from the frame buffer and displayed, virtually eliminating any perceptible lag time.